Bangalore: Eminent scientist Roddam Narasimha, the senior-most member of the Space Commission, has resigned to protest the blacklisting of former ISRO chairman G. Madhavan Nair and three others in connection with the Antrix-Devas spectrum deal, a senior official of the Indian space agency said Friday. "As Narasimha had submitted his resignation letter directly to the Prime Minister's Office, we do not have details on why he decided to quit. But we learn that he was perturbed over the government's recent action against the four top space scientists, including Nair," an official of the state-run Indian Space Research Organisation (ISRO) told IANS here on anonymity. Narasimha, 78, has been associated with the Space Commission for over two decades and has been its longest member.